/**
 * Copyright 2009 Sergio Bossa
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package com.googlecode.actorom.local.support;

import java.util.HashSet;
import java.util.Set;
import net.jcip.annotations.ThreadSafe;

/**
 * @author Sergio Bossa
 */
@ThreadSafe
public class SymbolicHostBinder {

    private static SymbolicHostBinder instance = new SymbolicHostBinder();
    private final Set<String> binds = new HashSet<String>();

    public static SymbolicHostBinder getInstance() {
        return instance;
    }

    public synchronized void bind(String symbolicHost) {
        if (!binds.contains(symbolicHost)) {
            binds.add(symbolicHost);
        } else {
            throw new SymbolicHostAlreadyBoundException("Symbolic host already bound to another topology: " + symbolicHost);
        }
    }

    public synchronized void unbind(String symbolicHost) {
        binds.remove(symbolicHost);
    }
}
